Trigui W, Hlel F
Faculty of Sciences, Laboratory of Spectroscopic and Optical Characterization of Materials, University of Sfax BP1171 3018 Sfax Tunisia.
RSC Adv. 2019 Aug 6;9(42):24291-24298. doi: 10.1039/c9ra02577d. eCollection 2019 Aug 2.
The exploration of ferroelectric hybrid materials is highly appealing due to their great technological significance. They have the potential to conserve power and amazing applications in information technology. In line with this, we herein report the development of a [(CH)N]BiCl tetra-alkyl hybrid compound that exhibits ferroelectric properties. The phase purity was confirmed by Rietveld refinement of the X-ray powder diffraction pattern. It crystallizes, at room temperature, in the monoclinic system with the 2/ space group. The outcome of temperature dependence of the dielectric constant proved that this compound is ferroelectric below approximately 238 K. The dielectric constants have been fitted using the modified Curie-Weiss law and the estimated values are close to 1. This confirms classical ferroelectric behavior. Raman spectroscopy is efficiently utilized to manifest the origin of the ferroelectricity, which is ascribed to the dynamic motion of cations as well as distortion of the anions. Moreover, the analysis of the wavenumbers and the half-width for δ(Cl-Bi-Cl) and ω(CH) modes, based on the order-disorder model, allowed us to obtain the thermal coefficient and activation energy near the para-ferroelectric phase transition.
铁电混合材料因其重大的技术意义而极具吸引力。它们具有节能潜力以及在信息技术领域的惊人应用。与此相符，我们在此报告一种表现出铁电性质的[(CH)N]BiCl四烷基混合化合物的研发情况。通过对X射线粉末衍射图谱进行Rietveld精修确认了相纯度。它在室温下结晶于单斜晶系，空间群为2/ 。介电常数随温度变化的结果证明，该化合物在约238 K以下是铁电体。介电常数已用修正的居里 - 外斯定律进行拟合，估计值接近1。这证实了经典的铁电行为。拉曼光谱被有效地用于揭示铁电性的起源，这归因于阳离子的动态运动以及阴离子的畸变。此外，基于有序 - 无序模型对δ(Cl - Bi - Cl)和ω(CH)模式的波数及半高宽进行分析，使我们能够获得顺电 - 铁电相变附近的热系数和活化能。
